HISTONE DEACETYLASE 9

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 金属依赖的组蛋白脱乙酰酶(HDAC)需要锌或铁来调节真核细胞中组蛋白和其他蛋白质中赖氨酸残基的乙酰化。HDAC8同工酶可能是第一类HDAC家族的典型成员，代表了理解该酶家族构效关系的范例。在这里，我们报道了与曲古菌素A和3-(1-methyl-4-phenylacetyl-1H-2-pyrrolyl)-N-hydroxy-2-propenamide(APHA)以新的晶型形成的HDAC8络合物的结构。APHA络合物的结构表明，羟甲酸根C=O基团没有以有利的几何构型与锌配位，这可能是由于其扩展体系的限制，而是接受来自Y306的氢键。此外，由于APHA只与该复合体不对称单元中的3个蛋白质分子中的2个结合，所以第三个单体的结构代表了HDAC8在未连接状态下的第一结构。对未连接和连接结构的比较表明，配体在L2环中诱导的构象变化可能伴随着底物结合和催化。此外，这些结构以及D101N、D101E、D101A和D101L变体的结构支持D101对L2环路功能至关重要的观点。然而，D101的氨基酸替换也可以引发Y111和W141的构象变化，从而扰乱底物结合部位。我们正在继续努力获得D101E突变体的更高分辨率的数据，并努力探索与HDAC8酶的钾结合位点。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Metal-dependent histone deacetylases (HDACs) require Zn2+ or Fe2+ to regulate the acetylation of lysine residues in histones and other proteins in eukaryotic cells. The HDAC8 isozyme is perhaps the archetypical member of the class I HDAC family and represents the paradigm for understanding structure-activity relationships in this enzyme family. Here, we report the structures of HDAC8 complexes with trichostatin A and 3-(1-methyl-4-phenylacetyl-1H-2-pyrrolyl)-N-hydroxy-2-propenamide (APHA) in a new crystal form. The structure of the APHA complex reveals that the hydroxamate C=O group does not coordinate to Zn2+ with favorable geometry, perhaps due to the constraints of its extended ¿¿ system, but instead accepts a hydrogen bond from Y306. Additionally, since APHA binds to only 2 of the 3 protein molecules in the asymmetric unit of this complex, the structure of the third monomer represents the first structure of HDAC8 in the unliganded state. Comparison of unliganded and liganded structures illustrates ligand-induced conformational changes in the L2 loop that likely accompany substrate binding and catalysis. Furthermore, these structures, along with those of the D101N, D101E, D101A, and D101L variants, support the proposal that D101 is critical for the function of the L2 loop. However, amino acid substitutions for D101 can also trigger conformational changes of Y111 and W141 that perturb the substrate binding site. We are continuing to work on getting higher resolution data for the D101E mutant, and working to explore potassium binding sites with the HDAC8 enzyme.